What is the life of gel batteries?

[headlight]

I'm having trouble following you as well?
How have I drained my batteries too quickly - unless you are referring to trying an inverter which turned on and instantly off and I am not doing anything to charge the batteries other than using the CTEK equipment as it was designed and professionally installed?
I am asking them for their opinion on the fact that it has been suggested to me that they can output too much current for the job they are designed for and could therefore have overcharged my batteries.

What I am saying is that you are the user therefore it is up to you to ensure that what you are doing is within the battery recommended specs.
Any problems caused by not staying within the specs of the battery are down to you.
I am sure that is what CTEK will say.
CTEK made the charger, they can't be held responsible as to how you have used it.

 

[ChrisL]

Autorouter has basically said this twice:

Your batteries should be charged at no more than 40a for the pair (20a each).

Your setup has been charging them at 100a.

QED.

I have to say I don't understand this, I was under the impression that the rate a lead acid battery charges at is defined by its internal resistance, which is why the current reduces as the internal resistance increases as it becomes more charged, are you saying it's possible to push more amps into a battery then its internal resistance would allow? My B2B can provide a 30 amp charge but when I had gel batteries if they were only a little discharged it would only provide 8 amps and I never saw more then 18 amps when they were down to 50%.

 

[headlight]

TheLifeofBrian I've just re read this thread and this is the second set of batteries you've goosed ?

 

[Hedgewitch]

This might be apples & oranges, but I have a small gel battery in a ride-on lawnmower; the mower is used a couple of times a year to cut a meadow and the rest of the year has a tow hitch and drags a small trailer around.

It lives in a non-insulated shed hooked up to a Ctek unit when not in use.

Both the battery and Ctek are at least ten years old . . . (and the only occasion the engine did not start first time was because we'd missed an annual service and it needed some TLC).

 

[TheLifeofBrian]

I have to say I don't understand this, I was under the impression that the rate a lead acid battery charges at is defined by its internal resistance, which is why the current reduces as the internal resistance increases as it becomes more charged, are you saying it's possible to push more amps into a battery then its internal resistance would allow? My B2B can provide a 30 amp charge but when I had gel batteries if they were only a little discharged it would only provide 8 amps and I never saw more then 18 amps when they were down to 50%.

I have to say that's exactly how I understood it

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[TheLifeofBrian]

TheLifeofBrian I've just re read this thread and this is the second set of batteries you've goosed ?

Yes I obviously bugger my batteries up on purpose and only £400 a time!

 

[SpeedyDux]

I had a gel hab battery that needed replacing. It was only 15 years old!

 

[Richard n Ann]

I have to say that's exactly how I understood it

When the batteries are discharged they will take whatever the charger is rated at. The internal resistance only comes up as they charge

 

[headlight]

Yes I obviously bugger my batteries up on purpose and only £400 a time!

So what you're saying is that if you get done for doing 100mph it's not your fault it's the car manufacturers fault for making and selling a car capable of breaking the speed limit.

 

[Richard n Ann]

So what you're saying is that if you get done for doing 100mph it's not your fault it's the car manufacturers fault for making and selling a car capable of breaking the speed limit.

Not quite, he didn't know he was doing 100mph

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[TheLifeofBrian]

So what you're saying is that if you get done for doing 100mph it's not your fault it's the car manufacturers fault for making and selling a car capable of breaking the speed limit.

I think we may be talking at cross purposes here.
How am I able to alter how much charge the CTEK units are putting into my batteries? And how am I responsible for them doing that?

 

[headlight]

I think we may be talking at cross purposes here.
How am I able to alter how much charge the CTEK units are putting into my batteries? And how am I responsible for them doing that?

You can't alter how the charger works but the onus is on you to ensure that the charger is suitable for your needs.
If it is not then it is your problem not the charger manufacturers problem and you have to suck up the result.
I cant see you getting anywhere with CTEK.
I suppose you could try the "professional " who fitted the charger ?

 

[Hedgewitch]

How am I able to alter how much charge the CTEK units are putting into my batteries? And how am I responsible for them doing that?

Did you set the 'mode' on your Ctek unit to AGM?

 

[AdrianChen]

I have to say I don't understand this, I was under the impression that the rate a lead acid battery charges at is defined by its internal resistance, which is why the current reduces as the internal resistance increases as it becomes more charged, are you saying it's possible to push more amps into a battery then its internal resistance would allow? My B2B can provide a 30 amp charge but when I had gel batteries if they were only a little discharged it would only provide 8 amps and I never saw more then 18 amps when they were down to 50%.

A wet lead acid battery if re-charged at a high voltage/current will start to produce heat during the process, sufficient to induce gassing and reduce the electrolyte level within the battery, so in the past many batteries relied on being topped up with water to cover the plates again as they depleted. The higher the voltage and current, the more gassing takes place and the more they needed topping up.

Commonly now leisure batteries are sealed/vented and do not require topping up, but in reality they are just made with higher electrolyte fill from new to allow for depletion, and failure often arises because the electrolyte becomes stronger as the water element is gassed off.

When Gel batteries are subjected to the same situation of being charged at high voltage/current the electrolyte, being a gel can't gas off in the same way, and can't be topped up, so they need to be kept within their specification or they will get damaged. Different manufacturers may use different Gels - I don't know, but the Victron/Sonnechein/Exide ones in my experience (Limited and out of date now!) were very reliable.

So a battery will accept a given charge current in proportion to the voltage being supplied - the higher the voltage the higher the acceptance rate, but at some point that will be sufficiently high to produce sufficient heat to "boil" or "Fizz" the electrolyte, or even buckle the plates. In selecting a charger the rule used to be for the charger to be a max of around 15% of the batteries AH capacity, 15amp for a 100amp battery. A "smart" charger (as AutoRouter has explained) may start it's programme by increasing its output voltage to a level where the batteries are accepting the chargers maximum output current. If this is 15amps the 100amp battery should cope, however if the charger can increase the voltage/current sufficiently the battery may accept far more, and the possibility exists for that level to damage a battery not designed for it.

One of the benefits with Lithium is the charge rate, because they can manage a very high charge current compared to LA, especially compared to cheap leisure batteries, and even purpose made deep cycle wet lead acid batteries such as the Trojan T105. Gels benefit is that they don't need any maintenance, gas very little if at all and can cope with deep cycles and PSOC storage better than most other LA types, but their downside is they are comparatively slow to recharge, and are not the best choice for high current loads, but they do work well as leisure batteries......

 

[ChrisL]

A wet lead acid battery if re-charged at a high voltage/current will start to produce heat during the process, sufficient to induce gassing and reduce the electrolyte level within the battery, so in the past many batteries relied on being topped up with water to cover the plates again as they depleted. The higher the voltage and current, the more gassing takes place and the more they needed topping up.

Commonly now leisure batteries are sealed/vented and do not require topping up, but in reality they are just made with higher electrolyte fill from new to allow for depletion, and failure often arises because the electrolyte becomes stronger as the water element is gassed off.

When Gel batteries are subjected to the same situation of being charged at high voltage/current the electrolyte, being a gel can't gas off in the same way, and can't be topped up, so they need to be kept within their specification or they will get damaged. Different manufacturers may use different Gels - I don't know, but the Victron/Sonnechein/Exide ones in my experience (Limited and out of date now!) were very reliable.

So a battery will accept a given charge current in proportion to the voltage being supplied - the higher the voltage the higher the acceptance rate, but at some point that will be sufficiently high to produce sufficient heat to "boil" or "Fizz" the electrolyte, or even buckle the plates. In selecting a charger the rule used to be for the charger to be a max of around 15% of the batteries AH capacity, 15amp for a 100amp battery. A "smart" charger (as AutoRouter has explained) may start it's programme by increasing its output voltage to a level where the batteries are accepting the chargers maximum output current. If this is 15amps the 100amp battery should cope, however if the charger can increase the voltage/current sufficiently the battery may accept far more, and the possibility exists for that level to damage a battery not designed for it.

One of the benefits with Lithium is the charge rate, because they can manage a very high charge current compared to LA, especially compared to cheap leisure batteries, and even purpose made deep cycle wet lead acid batteries such as the Trojan T105. Gels benefit is that they don't need any maintenance, gas very little if at all and can cope with deep cycles and PSOC storage better than most other LA types, but their downside is they are comparatively slow to recharge, and are not the best choice for high current loads, but they do work well as leisure batteries......

I think I made the mistake of assuming the charger was correctly set for GEL batteries, if it was set for AGM that would indeed be charging at too higher voltage, with the consequent damage that might occur.

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[AdrianChen]

I think I made the mistake of assuming the charger was correctly set for GEL batteries, if it was set for AGM that would indeed be charging at too higher voltage, with the consequent damage that might occur.

Well the key I think is that old "15%" rule because applying that when selecting a charger should ensure that during bulk mode the charger wont be able to supply too much current for the battery to cope.

 

[autorouter]

I have to say I don't understand this, I was under the impression that the rate a lead acid battery charges at is defined by its internal resistance, which is why the current reduces as the internal resistance increases as it becomes more charged, are you saying it's possible to push more amps into a battery then its internal resistance would allow?

The internal resistance plays a part, but is not the main determining factor in the charge rate. A battery has a 'resting voltage', which is the voltage at the battery terminals when it is not being charged and not under any load. Technically this is known as the battery internal electromotive force (EMF), and is due to the chemical process taking place inside the battery.

To charge a battery, you apply a voltage slightly higher than the internal EMF, resulting in an amps flow into the battery instead of out of it. This amps flow causes chemical reactions inside the battery, reversing the reactions that happened while the battery was discharging.

The amps flow will depend on the net voltage and the internal resistance. The net voltage is the difference between the internal EMF and the applied charger voltage. So typically the internal EMF (resting voltage) of a fairly flat battery is 12.0V, and the applied voltage would be maybe 13.2V initially. The net voltage is 13.2 - 12.0 = 1.2V. The internal resistance might be 0.02 ohms, so the amps flow would be 1.2 / 0.02 = 60A.

As you can see, a very small change in the applied voltage will result in a very big change in the amps flowing into the battery.

The way most chargers get round this problem is to decide what amps flow the battery will require, and go into constant current mode to supply it. So for example the DS250S will provide 20A of current, at whatever voltage is required to cause that current flow. As the battery charges, the internal EMF (resting voltage) slowly rises, and the charger compensates for this, keeping the amps flow constant at 20A. At some point the voltage will rise to a predetermined limit, called the absorption voltage, and the charger will recognise this, and decide that the first stage of charging has finished.

But the important take-away from this is that the charger supplies its maximum amps output for the whole of the first stage of the charging process.

 

[WanderingWheels]

Hi all,
Anyone any idea what could kill my gel batteries in only 18 months?
April last year I changed both batteries as the old AGMs had died - we got 110ah gel batteries from Alpha & they have been absolutely great all year but got to the Lincoln show Thursday (no ehu) & by Friday night they had both dropped to 11v
When the sun comes out they read up to 14v but turn a tap on & they drop like a brick to 12v
I've tried disconnecting one of them to see if it's just one dragging the other down but last night (Saturday) it dropped so low it turned the control panel off & the sun had been shining all day & the only thing plugged in was our 2 phones.

This is virtually the same thing that happened to the last pair of AGM batteries!
The only thing I can think is I tried the inverter (that is wired in) with a coffee machine but it wasn't big enough so turned it off.
It's a 600w pure sine inverter with a remote switch:
View attachment 953502

Other than that the Lincoln show is great

Any ideas anyone please?
Cheers Chris

Your gel batteries might be failing due to deep discharges, incorrect charging, or excessive loads from the inverter, especially if it struggled with the coffee machine. Check if the inverter is oversized for regular tasks like charging phones. Also, extreme temperatures or issues with the solar charging setup could be affecting battery health. Inspect all connections for corrosion or looseness, and monitor the battery voltage under various loads. If the problem continues, consider consulting a professional to examine the system or exploring warranty options from the battery manufacturer. If you exhaust these options and need new batteries, check out this battery guide and don't make the same mistake twice.

 

[TheLifeofBrian]

Your gel batteries might be failing due to deep discharges, incorrect charging, or excessive loads from the inverter, especially if it struggled with the coffee machine. Check if the inverter is oversized for regular tasks like charging phones. Also, extreme temperatures or issues with the solar charging setup could be affecting battery health. Inspect all connections for corrosion or looseness, and monitor the battery voltage under various loads. If the problem continues, consider consulting a professional to examine the system or exploring warranty options from the battery manufacturer. If you exhaust these options and need new batteries, check out this battery guide and don't make the same mistake twice.

Unfortunately people keep misunderstanding - I tried the inverter and it immediately switched off. I haven't used it since as it was obviously too small.
There have been no extremes - no heavy use or temperatures, just normal use. All connections are good & secure. As it has been suggested I allowed the batteries to be overcharged by the CTEK units I have sent them off to be checked under warranty as you have suggested.